Update

Posted: July 15, 2012 in Uncategorized

Water Rockets are really a summer project, so since the end of last summer there’s been a long period of inactivity. But since May I’ve been busy, I  have a new launcher built, from copper plumbing parts, and judging by the pressure tests I’ve done so far it’s promising to be a good one.

Due to the rain and wind that’s been with us for as long as I can remember, we’ve not had a chance to try it out yet.

I’ll upload some pics of the new launcher soon, and hopefully the weather will get better in the next few weeks and we can get the rockets flying.

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Video guide

Posted: July 21, 2011 in Uncategorized

This site has some really good info on making rockets. My release system is based on the videos here.

For information, the B&Q own brand (£1 a pop!) hose connectors are essentially identical to the Gardena system ones. Don’t bother with Hozelock though, as I ruined two connectors trying to take them apart – there doesn’t seem to be any way to get them apart without breaking the retaining clips 😦 (luckily they are on special in Tesco at the moment so didn’t cost much!)

New Launcher

Posted: July 21, 2011 in Uncategorized

Just finished putting together the new launching mechanism. This time the bottle release is based on a Hozelock/Gardena style hose connector.

Starting from the bottom right:

Same Schrader valve as before, this time in a 15mm pvc pipe end cap. A length of 15mm pipe is then connected to some re-inforced hose line (rated to 144 psi) and held in place with a jubilee clip. Oh, and both ends of the pipe have pipe inserts fitted to them – these strengthen the end of the pipe and prevent it collapsing from the pipe weld glue (which melts the plastic a bit) and the force from the jubilee.

The hose is then connected to a B&Q own brand hose connector with quick release. This is modified slightly, detailed below.

On the left I’ve connected a piece of coat-hanger wire with a jubilee clip to the release mechanism. The launch string will be attached to this wire.

On the right is the view down the barrel of the connector. I had to dismantle it and sand a couple of millimetres off the internal fitting to allow the bottle connector to lock in place properly.

Also these hose connectors have a no-return valve in them – basically a plastic stick with a washer to make a seal. The idea is that when you disconnect your spray gun or whatever the water flow stops. Unfotunately this is the wrong way round for a water rocket – I want to stop water going into it from above. If you remove the washer from the valve the plastic slides out, so I did that and refitted the valve the other way round. Hopefully it will stop the piping filling with water, although I haven’t tried it out yet.

 I’ve pressure tested the seals to 40 psi so far and everything has held perfectly.

Finally onto the last part of the setup, the bottle connector. This is made from a tap connector that’s designed to lock into the hose connector. I took off all he excess plastic using my dremel so that I was left with just the locking part and a tiny bit of shoulder. I’ve fitted this into a standard bottle top and glued it all up so that it makes a good seal. The seal wasn’t perfect, but a few wraps of PTFE tape round the threads on the bottle and it’s leak free.

Now I just have to mount it onto the wooden base and it’s time for some test firing!

Look what I just found!

Posted: July 18, 2011 in Uncategorized

Some polystyrene packaging that has a rather good shape to it…

Prototype 3-litre Rocket

Posted: July 18, 2011 in Uncategorized

I made this mock up of the Clovie 2 to test different methods for the joining of multiple bottles.

 

I did a dry run with compressed air inside once the glue was cured and the top joint gave way, shooting the top bottle straight up into the ceiling making a rather nasty dent, and scaring the shit out of the cat.

So the jointing method I’m going with is to use a section of a fourth bottle fitted inside the the joint as an O-ring, so the top and bottom bottles will be attached to it instead of each other. This should give a much larger area for the glue, thus a much stronger joint.

 

The Clovie 1

Posted: July 18, 2011 in design - rocket

Here’s a picture of the Cloveie 1 pre-launch on the pad.
This is a really basic design really taking no aerodynamics or weight considerations into account, hence why it didn’t work very well 😀

The 4 fins are cut from the sides of a San Miguel beer crate, the nose is the top of a second bottle with a paper extension. Inside the cone is a parachute made from a cut up black bin bag, and the top and parachute are tied on using basic super-market string. The fins are attached with brown packing tape, and the whole thing has been given a nice coat of orange spray paint and a bunch of stickers to help it on its way.

First Flight Test

Posted: July 18, 2011 in Flight Tests

This is the first flights of the first “proper” rocket (i.e. not just an empty bottle).

Having spoken to a couple of friends that know about this sort of stuff it seems there’s too much drag at the back and not enough weight at the front. The parachute failed to open properly, but I think this is mainly due to its abysmal height 😦